A damper device including an input element and an output element; an elastic body transmitting torque between the input element and the output element; and a rotary inertia mass damper having a mass body. The rotary inertia mass damper includes a sun gear, a carrier rotatably supporting pinion gears, and a ring gear that meshes with the pinion gears and serving as the mass body. A pair of washers is located on both sides of each pinion gear axially. The ring gear includes an annulus gear having internal teeth meshing with the pinion gears and a weight body fixed to the annulus gear such that the weight body is in contact with a side surface of the annulus gear. An inner circumferential surface of the weight body is supported in a radial direction by a tip of the pinion gear or an outer circumferential surface of the washer.

A torsional vibration damper that damps torsional vibration effectively in a low-speed range. In the torsional vibration damper, a spring holder is formed by apertures of an input element and an output element, and an elastic member is held in the spring holder. A first moveable range of a planetary element extending from an initial position in a drive direction is wider than a second movable range of the planetary element extending from the initial position in a counter direction.

A rotary inertia mass damper of a damper device is configured to include a planetary gear that includes a driven member with outer teeth, first and second input plate member as a carrier which rotatably supports a plurality of pinion gears, and a ring gear that meshes with the plurality of pinion gears and works as the mass body. The outer teeth of the driven member are arranged to be disposed outside first and second springs in a radial direction of the damper device. The driven member, the plurality of pinion gears and the ring gear are arranged to at least partially overlap with the first and second springs as viewed in the radial direction. A motion of the ring gear in the axial direction is restricted by the plurality of pinion gears.

A torque fluctuation inhibiting device includes a mass body, first and second centrifugal elements, and first and second cam mechanisms. The mass body is rotatable with a rotor and is also rotatable relatively to the rotor. Each of the first and second centrifugal elements receives a centrifugal force to be generated by rotation of the rotor and the mass body. When a relative displacement is produced between the rotor and the mass body in a rotational direction, the first cam mechanism converts the centrifugal force that acts on the first centrifugal element into a first circumferential force directed to reduce the relative displacement. When the relative displacement is produced between the rotor and the mass body in the rotational direction, the second cam mechanism converts the centrifugal force that acts on the second centrifugal element into a second circumferential force directed to reduce the relative displacement.

A torque fluctuation inhibiting device includes a mass body, a centrifugal element and a cam mechanism. The mass body is disposed to be rotatable with a rotor and be rotatable relatively to the rotor. The centrifugal element is disposed to receive a centrifugal force to be generated by rotation of the rotor and the mass body. When a relative displacement is produced between the rotor and the mass body in a rotational direction, the cam mechanism converts the centrifugal force that acts on the centrifugal element into a circumferential force directed to reduce the relative displacement. Additionally, when the torque fluctuations inputted to the rotor have a predetermined magnitude or greater, the cam mechanism makes the mass body freely rotate with respect to the rotor.

A torque fluctuation inhibiting device inhibits torque fluctuations in a rotor to which a torque is inputted. The torque fluctuation inhibiting device includes a mass body, a centrifugal element and a cam mechanism. The mass body is disposed to be rotatable with a rotor and be rotatable relatively to the rotor. The centrifugal element is disposed to receive a centrifugal force to be generated by rotation of the rotor and the mass body. The cam mechanism converts the centrifugal force acting on the centrifugal element into a circumferential force when a relative displacement is produced between the rotor and the mass body in a rotational direction. The circumferential force is directed to reduce the relative displacement.

A power transmission device includes an input-side rotary part to which a torque is inputted from an engine, an output-side rotary part, and a damper part. The output-side rotary part includes a first rotor and a second rotor. The first rotor is configured to be rotatable relative to the input-side rotary part. The first rotor is configured to be rotatable unitarily with the input-side rotary part at greater than or equal to a predetermined relative rotational angle. The second rotor is configured to be rotatable unitarily with the first rotor. The second rotor is configured to be rotatable relative to the first rotor at greater than or equal to the predetermined relative rotational angle. The damper part is configured to elastically couple the input-side rotary part and the output-side rotary part.

A vibration damping device for a motor vehicle, features a first movable element (13, 14) and a second movable element (15, 16) both rotatable around an axis X, at least one group of elastic members (25, 26) mounted between the first movable element and the second movable element and acting against rotation of the first movable element and second element with respect to one another, and a phasing member (32, 33) rotationally movable around the axis X. The first movable element (13, 14) and the second movable element (15, 16) are coaxial and capable of transmitting a torque. The phasing member (32, 33) includes a first portion (32) and a second portion (33), for arranging the elastic members of the at least one group in series so that the elastic members of each group deform in phase with one another.

A damper device that includes a first torque transmission path including a first elastic body that transmits torque between the input element and the output element; and a second torque transmission path disposed in parallel with the first torque transmission path and including first and second intermediate elements, a second elastic body that transmits the torque between the input element and the first intermediate element, a third elastic body that transmits the torque between the first intermediate element and the second intermediate element, and a fourth elastic body that transmits the torque between the second intermediate element and the output element.

A rotary inertia mass damper of a damper device is configured to include a planetary gear that includes a driven member with outer teeth, first and second input plate member as a carrier which rotatably supports a plurality of pinion gears, and a ring gear that meshes with the plurality of pinion gears and works as the mass body. The outer teeth of the driven member are arranged to be disposed outside first and second springs in a radial direction of the damper device. The driven member, the plurality of pinion gears and the ring gear are arranged to at least partially overlap with the first and second springs as viewed in the radial direction. A motion of the ring gear in the axial direction is restricted by the plurality of pinion gears.